Lieutenant Ingoldsby turned round sharply in the middle of shaving his left cheek.
"Good!" he exclaimed. "Very good. You've certainly hit upon the right notion, if you think it can be worked—and at once."
"It ought to be quite easy," Mark averred. "Just a steel-wire net in the shape of a fan, hinged from the trawler's cutwater and supported from pulleys at the end of beams shoved out like catheads over the bows. It would be lowered in front of her, below her water-line, to scoop up the mines, or drive them aside. There'd be scores of lives saved, sir."
"So I should think," assented the commander, proceeding with his shaving. "You ought to make a working model of the contrivance and submit it to the authorities. They're almost sure to adopt it, recognising you as a kind of expert on mine-sweeping. And now, there's something else I want to ask you. What has become of Heinrich Hilliger and his son, do you know? I have heard of your raid on the pigeon-loft at Sunnydene, and of the maps and charts that you found, and failed to bring away with you.'
"Max was drowned when the Atreus was mined," Mark explained. "And his father is believed to have gone back to Germany."
"Then whom do you suspect of having taken off the charts and things?" pursued Lieutenant Ingoldsby.
Mark could not explain this mystery. It had puzzled him ever since the night of its occurrence.
"You will be doing a service to your country," said the officer, "if you make a point of finding out exactly where those two are, and what they are doing. For my own part, I don't believe for a moment that Max Hilliger was drowned, or that his father has gone home to Germany. They are alien enemies, you know, and it is not to be wondered at if they are still in England—still even in Haddisport—working their level best to bring about the downfall of Great Britain."
Mark pondered over this recommendation while he was at breakfast in the engine-room, and resolved to make some investigations during his time of leave on shore. He also gave some thought to his invention for picking up explosive mines.
While he was drawing a plan of it, Lieutenant Ingoldsby, again at his post in the conning-tower, called out the command: